Burnishing-machine



PATENTBD'FEB 9, 1904. F. K. HATFIELD. BURNISHING MACHINE.

APPLICATION FILED APR. 11 1903.

10 MODEL.

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te-KM I UNITED STATES Patented February. 9, 1904.

PATENT OFFICE.

FRANK K. HATFIELD, OF BOSTON, MASSACHUSETTS, ASSIGNOR. TO FRANCIS F. HICKS, OF BOSTON, MASSACHUSETTS.

' ABIURONISHING-MACHINEL SPECIFICATION forming part of Letters Fatent No. 751,506, dated February 9,1904.

Application filed April 1, 1903. Serial No. 150,525. (No model.)

To all whom it may concern:

Be it known that I, FRANK K. HATFIELD, of Boston, in the county of-Sufi'olk and State of Massachusetts, have invented certain new and useful ImprovementsinBurnishing Machines,

of which the following is a specification.

This invention has for its object to provide a machine for burnishing metal surfaces in such manner as to imitate closely the rubbing motion of a hand-tool commonly used for this purpose and also adapted to perform the op- 7 4 represents a section on line 4 4 of Fig. 3.

Fig. 5 represents a section on line 5 5 of Fig. 3.

The same reference characters indicate the same parts in all the figures.

In the drawings, 04 represents a portable head, comprising a bearing portion 6 and an arm 7, projecting at an angle from the bearing portion and formed externally as a handle adapted to be grasped in the hand of the operator. The arm portion 7 is hollow, and through it extends a lever I), which is fulcrumed upon a pin or stud c, engaged with the arm portion 7. To the outer end of the lever 72 is fixed a burnishing-tool d, which may be made of any suitable relatively hard mate: rial susceptible of a high polish, the mineral known as bloodstone being preferred. The lever Z) is preferably provided with a clamping device adapted to engage the shank d of the tool cl. To this end the outer end of the lever may be enlarged, as shown at b, the enlarged portion being externally screwthreaded and provided with longitudinal slots 6 With the externally-threaded portion is engaged an internally-threaded tapered nut 6 When the nut is screwed home, it compresses the slotted portion of the enlargement, causing said portion to bind upon the shank of the tool dfl The inner end of'the Ilever b is provided with a longitudinal. slot 6*,

inner inflexible section f, journaled in a fixed bearing g and provided with a power-receiving member, such as a pulley f; secondly, an outer inflexible section 6, journaled in the bearing portion 6 of the Vertical head a, said section 6 having at its outer end a flange or enlargement 6 from the outer face of which the eccentric wrist-pin e projects; thirdly, an intermediate flexible section k, which is preferably a helically-coiled spring, one end of which is attached to the inner section f and the other to the outer section 6. Each of the sections f and e is provided with a flange 8, to which the said spring is attached, and a reduced inner portion 9, which enters the interior of the tube formed by the coiled spring. The spring is clamped upon the reduced portions 9 9 by means of clamping-sleeves 10 10, each of which embraces an end portion of the spring and is externally tapered. and screw-threaded, the tapered portions being provided with longitudinal slots 12. With said tapered and threaded portions are engaged internally-threaded and tapered nuts 13, which when turned home compress the slotted portions of the sleeves 10 upon the portions of the coiled spring inclosed therein, thus binding said portions firmly upon the reduced portions -9 of the shafts e and f.

It will be seen that when the inner section f is rotated-for example, by means of a belt running from a driving-shaft onto the pulley f its rotation is communicated through the flexible section it to the outersection 6, the rotation of which is caused as above described to oscillate the lever b and burnishing-tool d. The flexible section it enables the operator, who grasps the handle portion of the portable head, to move said head about over the work as may be desired, so that the tool may be applied to all parts of the surface to be burnished.

The length of the stroke of the burnishingtool may be varied by shifting the fulcrumpin 0 from one set of orifices in the armor handle portion 7 to another, a series of. pinreceiving orifices 14 being provided, said orifices being at different distances from the axis of rotation of the shaft-section e.

It is obvious that the above-described machine may be used by dentists for polishing and burnishing teeth, eithernatural or' arti-' ficial, and for producing other results which require the action of a rubbing-tool moving rapidly back and forth.

I claim- I V 1. i A burnishing device comprising a portable head having a bearing portion and a handle portion, a lever extending through and fulcrumed in said handle portion. and having a burnishing-tool at its outer end, and a drivingshaft adapted to oscillate said lever and tool, said shaft having an inner section journaled in a fixed bearing and provided with a powerreceiving member, an outer section journaled in said bearing portion and connected With said lever, and an intermediate flexible section, permitting free movements of the head.

2. A burnishing device comprising a portable head having a bearing portion and a handle portion, a lever extending through and fulcrumed in said handle portion and having a burnishing-tool at itsouter end, and adrivingshaft having an inner section journaled in a .fixed bearing and provided with a power-re- ..ceiving orifices located at different distances from the bearing portion, a detachable fulcrum-pinadapted to engage either set of orifices,.and a driving-shaft adapted to oscillate said lever and tool, said shaft having an inner section journaled in a fixed bearing and provided with a power-receiving member, an outer section journaled in said head and connected with said lever, and an intermediate flexible section, permitting free movements of the head.

In testimony whereof I have aflixed my signature in presence of two witnesses.

FRANK K. HATFIELD. Witnesses:

C; F. BROWN, E. BATGHELDER. 

